RepairPal Certified shops can diagnose and repair your 2006 Mercedes-Benz S350. They provide transparent pricing with a minimum 12-month or 12,000-mile warranty on repairs and services.
You have an issue with the PSE pump. It's an air pump that operates the locks and trunk. Check fuse under rear seat. Most likely blown since pump is drawing too much current from a leaky air line or trunk lock assy.